is your research concerned with any particular section within the treaty? And which time frame (roughly) are you considering for potential "secularization effects"? The 1920s and '30s or even beyond that?
Particularly writing about how secularization tended to began to and continued to overtake what had been a more religious worldview (after all, the war was almost a religious crusade as France, England, and Russia all vied against Germany), which all had Christianity in various forms as the "state" religion. As far as the treaty, the guilt clause and the redrawing of the European and Middle East maps and how self-determination really did not take place.
I think you are looking at the wrong treaty, treaty of Versailles did lead to secularism but in a insignificant way howe it did recognized freedom of religion (as long as they were christians) in long term treaty of Versailles became foundation for secular ideals in European Law